Development of a Lipopeptide Monolayer-Based Biosensor for Enhanced Detection of Glyphosate in Water

Development of a Lipopeptide Monolayer-Based Biosensor for Enhanced Detection of Glyphosate in Water

• Autor
• Priscila Sabbag Ferreira
• Co-autores
• Barbara Bianca Gerbelli , Bruna Cortez , Ana Cristina Honorato Castro-Kochi , Fabiola Lelis de Castro , Wendel Andrade Alves
• Resumo

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  In recent years, there has been an increased reliance on pesticides in agriculture for pest management. Given this trend, creating new analytical tools for detecting these substances in food and water has become imperative. In our study, we employed lipopeptides as functional analogs of the enzyme acetylcholinesterase (AChE) in phosphatidylcholine (PC) monolayers to detect glyphosate and N-(phosphonomethyl)glycine (PNG) in environmental samples. These lipopeptides incorporate hydrophilic amino acids such as L-serine (S), L-proline (P), L-arginine (R), L-tryptophan (W), and L-glycine (G), covalently bonded to a long aliphatic chain of 18 carbons. We used different molar ratios of lipopeptides (LP) to PC ([LP/PC]) and varied the PNG concentration from 1 to 15 µmol L^-1 for each monolayer composition. The Langmuir monolayer technique was utilized to examine the impact of LPs on the lipid monolayer. Notable changes in the adsorption isotherm were observed with increased LP amounts, including a reduction in the average molecular area and a decline in peak pressure. Increasing the PNG concentration for [LP/PC] at 0.5 left the collapse pressure unchanged, but the peak pressure declined for [LP/PC] at 1.0, stabilizing at approximately 23 mN/m. AFM imaging was used to assess the effect of varying LP amounts in the PC monolayer and the influence of PNG. The Nyquist diagram revealed an increase in charge transfer resistance due to the ITO's modification when the monolayer was present and after the pesticide was added, suggesting that the monolayer adheres to the ITO surface and that the pesticide interacts with this monolayer. A calibration curve was devised by adjusting the PNG concentration, yielding a detection limit (LOD) of 24 nmol L^-1. This result is particularly promising; when using the same lipopeptide in an aqueous medium as a colorimetric biosensor, we achieved a LOD of approximately 0.3 µmol L^-1, highlighting the electrochemical biosensor's exceptional sensitivity.

   

• Palavras-chave
• DPPC, lipopeptides, glyphosate, Langmuir, monolayers, biosensor
• Modalidade
• Pôster
• Área Temática
• Materiais Funcionais Avançados